In the generic WO 2009/149776 A1 several variants of a steering wheel unit are described with a steering wheel body and an air bag module accommodated in the hub area of the steering wheel body. Several concepts were proposed for positioning the air bag module in the steering wheel body, which all have in common that the axial positioning is effected by means of several positioning units (first positioning units), wherein each positioning unit has a positioning element on the steering wheel side with a rigid, level positioning surface and a positioning element on the airbag module side with a level positioning mating surface parallel to it. The positioning element on the steering wheel side and the positioning element on the air bag module side are made of plastic, in particular thermoplastic. In the normal operating condition of the motor vehicle, the positioning surface and the positioning mating surface are pressed against each other by the horn springs acting in the axial direction.
In the exemplary embodiments of WO 2009/149776 A1 which have advantages because of their ease of assembly and especially because of their problem-free disassembly, additional non-axial positioning units (second positioning units) are provided which act exclusively in the non-axial direction. In this case, the axial positioning units just described also act exclusively in an axial direction. In addition to the many advantages which the generic steering wheel unit exhibits, a disadvantage was also found in the practical tests, namely that it can happen, at least in very unfavorable constellations that the axially acting positioning units are exposed to some wear and tear, wherein the wear and tear can also manifest itself with noise generation. It cannot be ruled out with certainty that this wear and tear, over the operating life, expectancy results in a less accurate Z axis positioning. Although the operating safety of the air bag module or the steering wheel unit is not adversely affected by this, such wear and tear is naturally undesirable.